Pfizer's Phase 2 Study of Trispecific Antibody Positive in Moderate to Severe Atopic Dermatitis

• Study met primary endpoint, demonstrating statistically significant increase in the percentage of participants achieving EASI-75 at Week 16 across all doses tested, compared to placebo
• Tilrekimig (PF-07275315) was well-tolerated with a favorable safety profile
• Tilrekimig has the potential to be a first-in-class, once-monthly trispecific antibody targeting interleukin-4 (IL-4), interleukin-13 (IL-13), and thymic stromal lymphopoietin (TSLP) for multiple chronic Type 2 (Th2) inflammatory conditions including atopic dermatitis, asthma, and chronic obstructive pulmonary disease (COPD)
• Based on encouraging results, Pfizer plans to accelerate tilrekimig to Phase 3 development, with a pivotal study in atopic dermatitis on track to start this year

Pfizer Inc. (NYSE:PFE) today announced positive topline results from a Phase 2 study investigating tilrekimig (PF-07275315) in adults with moderate to severe atopic dermatitis. The study met its primary efficacy endpoint, demonstrating a statistically significant increase in the percentage of participants achieving EASI-75* (≥ 75% reduction in the Eczema Area and Severity Index) at Week 16, compared to placebo. In Stage 2 of the study, which evaluated monthly dosing regimens, tilrekimig showed competitive efficacy. The placebo-adjusted percentage of participants achieving EASI-75 at Week 16 was:

• 38.7% for the low tested dose;
• 51.9% for the middle tested dose; and
• 49.4% for the high tested dose.

The two highest dose levels tested with tilrekimig strongly suggest potentially meaningful improvements to approved standard of care biologics. Tilrekimig is an investigational trispecific antibody that simultaneously targets interleukin-4 (IL-4), interleukin-13 (IL-13), and thymic stromal lymphopoietin (TSLP), with the potential to be a once-monthly treatment option for multiple chronic inflammatory conditions driven by an overactive Type 2 (Th2) immune response, without affecting receptors on healthy cells.

"We are encouraged by the topline Phase 2 results for tilrekimig, which show that combining the potent inhibition of IL-4/13 and TSLP pathways has the potential to deliver improved efficacy over the standard of care for atopic dermatitis," said Mike Vincent, Chief Inflammation & Immunology Officer at Pfizer. "We plan to advance a broad clinical development program for tilrekimig, a potential first-in-class trispecific antibody discovered at Pfizer, in atopic dermatitis and other Th2-mediated inflammatory diseases including asthma and COPD."

Tilrekimig was well-tolerated with a favorable safety profile and no dose dependent safety signals; adverse event (AE) rates were comparable to placebo. The most common AEs were infections and infestations, skin and subcutaneous tissue disorders and general disorders, and administration site reactions. Three serious adverse events (SAEs) were observed, which were all considered to be unrelated to treatment. Of note, the observed frequency of conjunctivitis in this study was lower than rates reported with IL-4 receptor alpha inhibitors.

The Phase 2 study is an ongoing randomized, double-blind, placebo-controlled trial in adults with moderate to severe atopic dermatitis. It is being conducted in four overlapping stages:

• Stage 1 tested a high dose of tilrekimig versus placebo. In addition, Stage 1 included an arm testing a high dose of ompekimig (PF-07264660), an investigational trispecific antibody targeting IL-4, IL-13, and interleukin-33 (IL-33), versus placebo. Stage 1 has concluded and both tilrekimig and ompekimig groups met the primary endpoint.
• Stage 2 was a dose-ranging study in which participants received either tilrekimig or placebo.
• Stage 3 is an ongoing study in which participants who previously received biologic treatments receive either tilrekimig or placebo.
• Stage 4 is an ongoing dose-ranging study in which participants receive either ompekimig or placebo.

In addition to the ongoing Phase 2 study in atopic dermatitis, Pfizer is studying tilrekimig in an ongoing Phase 2 study in asthma and the company recently initiated a Phase 2b/3 study of tilrekimig in chronic obstructive pulmonary disease (COPD). Phase 3 planning for atopic dermatitis is ongoing, with a pivotal study on track to start this year.

Detailed results from the Phase 2 study of tilrekimig will be submitted to a future medical meeting and a peer-reviewed journal. Pfizer plans to share results from the ongoing portions of the study in the future, pending completion.

About Atopic Dermatitis

Atopic dermatitis is more than "just a rash." It is a chronic Type 2 (Th2) inflammatory skin condition, affecting people of all ages and genders around the world.^i,ii Atopic dermatitis is the most common form of eczema, and sometimes the terms are used interchangeably.ⁱⁱⁱ The most frequent symptom of atopic dermatitis is itchy skin, which can lead to rashes, pain, and poor sleep.ⁱⁱⁱ The condition can be debilitating, disrupting patients' daily lives, and negatively affecting their emotional well-being. Many patients do not experience a clinically meaningful response to currently available treatments, signaling a critical need for further innovation in this class of medicines.

About Pfizer: Breakthroughs That Change Patients' Lives

At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products, including innovative medicines and vaccines. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For 175 years, we have worked to make a difference for all who rely on us. We routinely post information that may be important to investors on our website at www.Pfizer.com. In addition, to learn more, please visit us on www.Pfizer.com and follow us on X at @Pfizer and @Pfizer News, LinkedIn, YouTube and like us on Facebook at Facebook.com/Pfizer.

Disclosure Notice

The information contained in this release is as of March 9, 2026. Pfizer assumes no obligation to update forward-looking statements contained in this release as the result of new information or future events or developments.

This release contains forward-looking information about tilrekimig (PF-07275315), an investigational trispecific antibody, including its potential benefits; results from the Phase 2 study of tilrekimig in participants with moderate to severe atopic dermatitis; Pfizer's investigational inflammation and immunology portfolio, and anticipated trial starts and clinical development plans, including plans to accelerate tilrekimig to Phase 3 development, with a pivotal study in atopic dermatitis planned to start this year, as well as their potential benefits, that involves substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. Risks and uncertainties include, among other things, the uncertainties inherent in research and development, including the ability to meet anticipated clinical endpoints, commencement and/or completion dates for our clinical trials, regulatory submission dates, regulatory approval dates and/or launch dates, as well as the possibility of unfavorable new clinical data and further analyses of existing clinical data; risks associated with initial, preliminary or interim data; the risk that clinical trial data are subject to differing interpretations and assessments by regulatory authorities; whether regulatory authorities will be satisfied with the design of and results from the clinical studies; whether and when drug applications may be filed in any jurisdictions for tilrekimig or any other product candidates for any potential indications; whether and when any such applications may be approved by regulatory authorities, which will depend on myriad factors, including making a determination as to whether the product's benefits outweigh its known risks and determination of the product's efficacy and, if approved, whether tilrekimig or any such other product candidates will be commercially successful; decisions by regulatory authorities impacting labeling, manufacturing processes, safety and/or other matters that could affect the availability or commercial potential of tilrekimig or any such other product candidates; risks and uncertainties related to issued or future executive orders or other new, or changes in, laws or regulations; uncertainties regarding the impact of COVID-19 on Pfizer's business, operations and financial results; and competitive developments.

A further description of risks and uncertainties can be found in Pfizer's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, and in its subsequent reports on Form 10-Q, including in the sections thereof captioned "Risk Factors" and "Forward-Looking Information and Factors That May Affect Future Results", as well as in its subsequent reports on Form 8-K, all of which are filed with the U.S. Securities and Exchange Commission and available at www.sec.gov and www.pfizer.com.

*EASI-75 is the industry standard for measuring how effectively a treatment candidate reduces atopic dermatitis (eczema) severity and extent from baseline

ⁱ Laughter MR, Maymone MBC, Mashayekhi S, et al. The global burden of atopic dermatitis: lessons from the Global Burden of Disease Study 1990–2017*. British Journal of Dermatology. 2021;184(2):304-309. doi:10.1111/bjd.19580

ⁱⁱ Choragudi S, Yosipovitch G. Trends in the Prevalence of Eczema Among US Children by Age, Sex, Race, and Ethnicity From 1997 to 2018. JAMA Dermatol. 2023;159(4):454-456.

ⁱⁱⁱ Eczema (contact dermatitis): Symptoms, causes, & treatment | National Eczema Association

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